Odemuyiwa O, Poloniecki J, Malik M, Farrell T, Xia R, Staunton A, Kulakowski P, Ward D, Camm J
Department of Cardiological Sciences, St George's Hospital Medical School, London.
Br Heart J. 1994 Jun;71(6):521-7. doi: 10.1136/hrt.71.6.521.
To examine the influence of the duration of follow up on the values of heart rate variability (HRV) and the left ventricular ejection fraction (LVEF) for predicting mortality after infarction.
HRV is an index of autonomic balance that identifies patients at a high risk of arrhythmic events. The index is most depressed during the first few weeks after myocardial infarction whereas left ventricular function tends to deteriorate with time.
The value of depressed HRV measured before discharge from hospital for predicting mortality after infarction should decline with time.
The HRV and the LVEF were assessed in 433 survivors of a first acute myocardial infarction: HRV < 20 units and LVEF < 40% were taken as cut off points. Kaplan-Meier survival functions for total cardiac mortality and sudden cardiac death were calculated for the whole five year follow up period and for different intervening periods.
During follow up of four weeks to five years there were 46 (10.6%) deaths and 15 (3.5%) patients died suddenly. Within the whole follow up period, HRV < 20 units and LVEF < 40% were both strongly associated with total cardiac mortality (p < 0.0001), but HRV was an independent predictor of total cardiac mortality only during the first six months of follow up. There were no deaths predicted by HRV < 20 units after the first year of follow up whereas LVEF < 40% had a sensitivity of 43% and a positive predictive accuracy of 9% for predicting death during this period. HRV < 20 units was better than LVEF < 40% in predicting sudden deaths during the first year of follow up but was an independent predictor only of those sudden deaths occurring within six months of infarction.
The duration of follow up affects the prediction of sudden death and total cardiac mortality from HRV. Reduced HRV as measured before discharge from hospital does not seem to retain independent prognostic value after six months of follow up. These findings have potential implications for the serial evaluation of HRV and for the prevention of sudden death after myocardial infarction.
探讨随访时间对心率变异性（HRV）值及左心室射血分数（LVEF）预测心肌梗死后死亡率的影响。
HRV是自主神经平衡的指标，可识别心律失常事件高危患者。该指标在心肌梗死后最初几周最为降低，而左心室功能则随时间趋于恶化。
出院前测得的降低的HRV预测心肌梗死后死亡率的价值应随时间下降。
对433例首次急性心肌梗死幸存者进行HRV和LVEF评估：HRV<20单位和LVEF<40%作为截断点。计算整个五年随访期及不同中间期的总心脏死亡率和心源性猝死的Kaplan-Meier生存函数。
在4周至5年的随访期间，有46例（10.6%）死亡，15例（3.5%）患者心源性猝死。在整个随访期内，HRV<20单位和LVEF<40%均与总心脏死亡率密切相关（p<0.0001），但HRV仅在随访的前6个月是总心脏死亡率的独立预测因子。随访1年后，HRV<20单位未预测到死亡，而在此期间LVEF<40%预测死亡的敏感性为43%，阳性预测准确性为9%。随访第1年，HRV<20单位预测心源性猝死优于LVEF<40%，但仅为梗死6个月内发生的心源性猝死的独立预测因子。
随访时间影响HRV对心源性猝死和总心脏死亡率的预测。出院前测得的HRV降低在随访6个月后似乎不具有独立的预后价值。这些发现对HRV的系列评估及心肌梗死后心源性猝死的预防具有潜在意义。
